Permafrost Vulnerability from multiple Essential Climate Variables (PVE)
Permafrost is a key indicator for global climate change and hence considered as an Essential Climate Variable (ECV). Current studies show a warming trend of permafrost globally and an increasing risk of permafrost thaw. While permafrost is defined as the thermal state of the subsurface, it is greatly influenced by changes in the surface energy balance, as it is tightly connected to the atmosphere, biosphere, geosphere and cryosphere. Continued climate warming induces widespread permafrost thaw, which leads to near-surface permafrost loss at local to regional scales, impacting ecosystems, hydrological systems, soil carbon accumulation and decomposition, greenhouse gas emissions, and infrastructure stability. However, the permafrost-climate interactions are complex and not fully understood yet and thus cannot be represented in global climate models. One approach is to examine permafrost’s vulnerability to changes in the surface energy budget, which can induce degradation and thaw, by integrating negative and positive feedbacks, such as topography, soil, water, snow and vegetation. Permafrost’s susceptibility to changes of one component is important but more importantly the interplay between the different feedbacks and their combined effect on the thermal state of the ground is of interest.
ECVs of relevance for describing the thermal state of permafrost, which can be monitored with remote sensing are land surface temperature, land cover, soil moisture, snow cover, and freeze/thaw state. Fire and albedo are additional important observables useful for understanding soil thermal regimes and disturbances in the permafrost-climate feedback system. Further, two modelled permafrost ECV products were published, the thermal state of permafrost and active layer thickness, providing the basis to assess the spatial and temporal trends in the permafrost domain across two decades. For all of these, ongoing ESA Climate Change Initiative projects generate global earth observation products of high quality. For the first time there is an extensive database of permafrost related earth observation data available, permitting to profoundly assess the permafrost-climate dynamics and the effect of the individual feedback components, as well as investigating the spatial and temporal heterogeneous responses.
Therefore, the objective of this project is to assess permafrost vulnerability from spatiotemporal variability of established ECVs and other earth observation products across the circumpolar Arctic from 2000 to present. By conducting spatiotemporal variability analyses of the individual parameters, a better understanding of the underlying dynamics will be established, differentiated between positive and negative feedbacks and a permafrost vulnerability assessment conducted.
Research Fellow: Alexandra Runge
Host Institution: AWI (potsdam)